Not working during the school year, worked the summer after my freshman year (at Eckerds, hehe), and the summer after my junior year. After my junior year, I got an awesome internship that paid mad cash - basically enough $ for a full year of school in 12 weeks (they gave me a scholarsip included in that total).
I'm pretty sure the main reasons I got that was my high GPA and extracurriculurs, so I would say it definitely was worth NOT working and instead getting the GPA and activities to boost the resume. But I might be biased because I had an academic scholarship that covered all tuition & fees, and my parents picked up the room and board tab willingly..